Problem: A permutation p is an ordered group of numbers p1, p2, ..., pn, consisting of n distinct positive integers, each is no more than n. We'll define number n as the length of permutation p1, p2, ..., pn.

Simon has a positive integer n and a non-negative integer k, such that 2k ≤ n. Help him find permutation a of length 2n, such that it meets this equation: <image>.

Input

The first line contains two integers n and k (1 ≤ n ≤ 50000, 0 ≤ 2k ≤ n).

Output

Print 2n integers a1, a2, ..., a2n — the required permutation a. It is guaranteed that the solution exists. If there are multiple solutions, you can print any of them.

Examples

Input

1 0


Output

1 2

Input

2 1


Output

3 2 1 4


Input

4 0


Output

2 7 4 6 1 3 5 8

Note

Record |x| represents the absolute value of number x. 

In the first sample |1 - 2| - |1 - 2| = 0.

In the second sample |3 - 2| + |1 - 4| - |3 - 2 + 1 - 4| = 1 + 3 - 2 = 2.

In the third sample |2 - 7| + |4 - 6| + |1 - 3| + |5 - 8| - |2 - 7 + 4 - 6 + 1 - 3 + 5 - 8| = 12 - 12 = 0.

Solution (in JAVA):

Solution:
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.Writer;
import java.math.BigInteger;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.util.StringTokenizer;
public class Main {
    public interface SpaceCharFilter {
        public boolean isSpaceChar(int ch);
        }
    class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private SpaceCharFilter filter;
        public InputReader(InputStream stream) {
            this.stream = stream;
        }
        public int read() {

            if (numChars == -1)

                throw new InputMismatchException();

            if (curChar >= numChars) {

                curChar = 0;

                try {

                    numChars = stream.read(buf);

                } catch (IOException e) {

                    throw new InputMismatchException();

                }

                if (numChars <= 0)

                    return -1;
            }
            return buf[curChar++];
        }
        public int readInt() {

            int c = read();

            while (isSpaceChar(c))

            c = read();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9')
            throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }
        public long readLong() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }
        public String readString() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }
        public boolean isSpaceChar(int c) {
            if (filter != null)
                return filter.isSpaceChar(c);
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }
        public String next() {
            return readString();
        }
    }
class OutputWriter {
        private final PrintWriter writer;
        public OutputWriter(OutputStream outputStream) {
            writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
        }
        public OutputWriter(Writer writer) {
            this.writer = new PrintWriter(writer);
        }
        public void print(Object...objects) {
            for (int i = 0; i < objects.length; i++) {
                if (i != 0)
                    writer.print(' ');
                writer.print(objects[i]);
            }
        }
        public void printLine(Object...objects) {
            print(objects);
            writer.println();
        }
        public void close() {
            writer.close();
        }
        public void flush() {
            writer.flush();
        }
        }
    /**
     * @param args
     */
    InputReader in= new InputReader(System.in);
    OutputWriter out = new OutputWriter(System.out);
    StringTokenizer tok;
        public static void main(String[] args) throws IOException
        {
           new Main().run();
        }
        void run() throws IOException
        {       
           solve();
           out.flush();
           tok=null;
        } 
     
        void solve() throws IOException{
            /*
             * tha dwsw mia poli gamati lisi :P
             * arxika, an k=0 apla ta ektipwnw 1 2 3 ktlp
             * estw k diaforo tou miden
             * epilegw  a1=1,a2=k+1 kai gia kathe (a2i-1,a2i) isxei a2i-1>a2i
             * tote:
             * ehw ta eksis
             *  (a2-a1) + A -|  a1-a2 + A| 
             *  estw  a1-a2<=A, tote:
             *  (a2-a1) + A  +(a2-a1) -A = 2(a2-a1)=2(k+1-1)=2k
             *  opote auto pou menei einai na dw gia kathe (n,k) na bgalw A tetoio wste  A>k
             *   to opoio isxei  an topothetisoume ta  a3=2*n,a4=2, a5=2*n-1,a5=3 ktlp
             *   prosexontas na min pesoume pote panw sto k+1 (an  pesoume se peritto  meiwnoume, alliws auksanoume)
             *   auto einai profanes oti isxei :-)
             *  
             */
            int n=in.readInt();
            int k=in.readInt();
      
            
            if (k==0){
                for (int i=1;i<=2*n;++i){
                    out.print(i+" ");
                    
                
                }
            }else{
                int a=1;
                int b=k+1;
                out.print(a+" "+b+" ");
            
                int r=2*n;
                int l=2;
                while (true){
                    if (l>=r) break;
                    if (l==b) l++;
                    if (r==b) r--;
                    out.print(r+" "+l+" ");
                    
                
                    r--;
                    l++;
                    
                }
            }
            
            
        }
}